 Hi everyone, my name is Leah. I'm your lead course instructor here at Advanced E clinical training And I want to welcome you to our last installment of the Anatomy and Physiology series Our lesson today is going to be the integumentary system. Oh right So the integumentary system some functions Include protection so the skin protects deeper tissues from mechanical damage chemical damage ultraviolet radiation as well as bacteria and Also thermal or heat damage Also the integumentary system helps with temperature regulation So our skin helps with heat loss or heat retention and is controlled by the central nervous system Also the integumentary system helps with elimination So the skin helps in secretion of urea and urea acid through perspiration produced by the spec lands also This system helps as it acts as a synthesizer So what that means is our skin helps to synthesize by vitamin D through modified cholesterol molecules in the skin by the sunlight And then of course sensation The integumentary system has sensory receptors that can recognize heat cold touch pressure and pain The integumentary system includes of course our skin our hair our fingernails Our toenails the sebaceous glands and our sweat glands So we'll start talking about this skin structures of this skin Now the skin is composed of two kinds of tissue the outer upper dermis and then the underlying dermis So you can see here in this Picture that the epidermis is the outer Part of the skin and it's comprised mostly of squalamus epithelium cells And it's that's capable of characterizing or becoming hard and tough then underneath the epidermis We have the dermis and this underlying dermis mostly consists of dense connected tissue Then underneath the dermis we have the subcutaneous tissue, which is mostly fat So let's start talking a little bit about the dermis So the dermis includes a papillary layer and this is This is the layer that's directly underneath the epidermis So this layer contains endings of capillaries limp vessels and sensory neurons It has a loose network of connected tissue that helps to provide nutrients to the skin and also helps With a sensory perception and temperature regulation Next we have the reticular layer and this is the deepest skin layer it contains blood vessels sweat and oil glands and deep pressure receptors Next we have the collagen so collagen fibers are responsible for the toughness of the dermis they also attract and Bind to water helping to keep our helping to keep our skin hydrated Then we have the elastic fibers elastic fibers Does of course exactly what it sounds like it does it gives our skin its elasticity when we are young and Unfortunately as we age the number of this of the collagen and elastic fibers decreases also The subcutaneous tissue loses fat Of course, there are blood vessels that are part of the dermis and that helped to Supply and keep the dermis alive. It helps also to maintain body temperature And then of course there is the nerve supply. So the dermis has a rich Nerve supply many of those nerve endings have specialized receptors That can help send messages back to the central nervous system when they are stimulated by environmental factors So here we have the epidermis in the epidermis. We have epithelial tissue and The epidermis is a vascular. So what that means is it has no blood supply of its own Next you have The keratin sites most of the cells in the epidermis are these Keratin sites which produce keratin. It's a fibrous Protein that help make the epidermis very tough For its protective layer. So that's important You have the stritum basali and that's the deepest layer of the epidermis and it's lies closer to the dark closest to the dermis It has epidermal cells that receive nutrients from the dermis Next we have this stritum has spinosum and this is the layer of the epidermis found between The granulosum and the basali and this layer is composed of polyhydrocharitonites that join together with The decimamones and then next underneath there you have the stritum granulosum And this layer becomes flatter and increasingly full of keratin and Last but not least then you have The lucidum and the lucidum is found in the palms of our hands and the soles of our feet Where the skin is hairless and thick Continuing on with the epidermis you have the stratum corneum and this is the outermost layer It's very thick and it accounts for about three quarters of the epidermal thickness There's cornified cells and that shingle like dead cells filled with keratin are known as cornified cells First we have the keratin and this is a strong protein found in the stratum corneum allowing it to protect the deeper cells from the hostile external environment We have melanin and melanin is a pigment that ranges in color from yellow to brown to black and it is produced by cells called the melanocytes found chiefly and The stratum result Next we have the melanosomes and the as the melanocytes produce melanin It accumulates melanin zones, which are granules that move to the melanocytes where they are taken up by the nearby keratocytes Next in the integumentary system We have hair and hair follicles because our hair is part of this integumentary system So we'll know what hair is. It's produced by our hair follicle And it is a flexible epithelial structure We have the root. So the root is the part of the hair enclosed in the follicle We have this shaft So the hair shaft projects from the surface of the scalp or the skin And then we have the formation. So hair is formed by a division of the strata and the sully epithelium cells In the matrix of the hair bulb at the inferior end of the follicle The composition so each hair is made up of a central core known as the medulla surrounded by the cortex layer And then we have the cuticle. So the cuticle is the most heavenly heavily keratinized area Providing strength and helps keep the inner hair layers tightly connected Continuing on with our hair and hair follicles So hair pigment is created by melanocytes in the hair ball that helps her produce hair color from pale blonde to pitch black Our hair follicles are compound structures the epidermal sheath So the inner epidermal sheath is composed of epithelial tissue and forms the hair We have the dermal sheath so the outer dermal sheath is dermal connective tissue And this dermal region helps to supply blood to the epidermis And then there's the papula which helps to provide the blood supply to the matrix of the hair ball Moving on to our nails So here now folds are the borders of the now that over that are over a lot by skin folds We have the cuticle the cuticles that fix that thick proximal Nail fold and that is known as the cuticle we have the now bed The now bed is actually the stratum basali of the epidermis extending beneath the nail The now matrix is responsible for the now growth And our nails are transparent in colorless, but they look pink because of the rich supply of blood and The lanula in this the exception to the pinkish color of the nails is the region over The thickened nail matrix that appears as white Or like a white crescent So moving on to the cutaneous glands of the anti-humitary system So exit so cutaneous glands are executing glands They're all Exocrine glands and release their secretions to the skin surface through ducts and fall into two groups the sebaceous glands and the sweat glands So sebaceous glands of or oil glands are found all over the skin except on the palms of the hands and the soles of the feet This the sebaceous glands produce sebum and that's a mixture of oily substances and fragmented cells and it helps it to Lubricate and keep the skin soft and moist. It also helps to prevent hair from becoming brittle Next we have our sweat glands And they're widely sweat glands are widely distributed in the skin and there are two types of Sweat glands. We have the echocrine glands and These types of sweat glands are More numerous and found all over the body. They produce sweat In which mostly water salts vitamin C that a ball of waste and lactic acid These type of sweat glands also help with the body's heat regulating system The last of the two sweat glands we have the aprican glands and These glands are Combined to the axillary and the genital areas of the body and they were a little bit larger than The aprican glands their secretions contain fatty acids and proteins and they begin to function during puberty under the influence of androgens so this Lesson here the integumentary system was a very short and sweet Not nearly as detailed as the others. So that's why I left it for last but of course And you all know if you have any questions or concerns or if you need me to clarify anything with you You can always email me And I will get back to you just as soon as I can. Thanks so much. We'll see you again soon